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Simon Peyton Jones pushed to branch wip/forall-vis-coercions at <a href="https://gitlab.haskell.org/ghc/ghc">Glasgow Haskell Compiler / GHC</a>
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Commits:
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<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/275cafcb4f0045dde91c5ca1d0d564baf426afc4">275cafcb</a></strong>
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<span> by Simon Peyton Jones </span> <i> at 2023-07-11T08:32:51+01:00 </i>
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3 changed files:
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compiler/GHC/Core/Lint.hs
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compiler/GHC/Core/TyCo/Rep.hs
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docs/core-spec/core-spec.mng
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Changes:
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<a href="https://gitlab.haskell.org/ghc/ghc/-/commit/275cafcb4f0045dde91c5ca1d0d564baf426afc4#36a42448a83a9d1f6df8475f03ead2eed199dd8e"><strong style="font-weight: bold;">compiler/GHC/Core/Lint.hs</strong></a>
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<td class="line_content match" style="color: rgba(31,30,36,0.24); padding: inherit;" bgcolor="#fbfafd">@@ -2255,9 +2255,13 @@ lintCoercion co@(ForAllCo { fco_tcv = tcv, fco_visL = visL, fco_visR = visR</td>
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2255
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<td class="new_line diff-line-num" data-linenumber="2255" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
2255
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC2255" class="line" lang="haskell"> <span class="p">;</span> <span class="n" style="color: #333;">lintForAllBody</span> <span class="n" style="color: #333;">tcv'</span> <span class="n" style="color: #333;">rty</span></span>
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2256
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<td class="new_line diff-line-num" data-linenumber="2256" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
2256
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC2256" class="line" lang="haskell"></span>
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<td class="old_line diff-line-num" data-linenumber="2257" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
2257
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<td class="new_line diff-line-num" data-linenumber="2257" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
2257
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC2257" class="line" lang="haskell"> <span class="p">;</span> <span class="n" style="color: #333;">when</span> <span class="p">(</span><span class="n" style="color: #333;">isCoVar</span> <span class="n" style="color: #333;">tcv</span><span class="p">)</span> <span class="o" style="font-weight: 600;">$</span></span>
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<td class="old_line diff-line-num old" data-linenumber="2258" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
2258
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<td class="new_line diff-line-num old" data-linenumber="2258" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
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<td class="line_content old" style="padding: inherit;" bgcolor="#fbe9eb"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>-<span id="LC2258" class="line" lang="haskell"> <span class="n" style="color: #333;">lintL</span> <span class="p">(</span><span class="n" style="color: #333;">almostDevoidCoVarOfCo</span> <span class="n" style="color: #333;">tcv</span> <span class="n" style="color: #333;">body_co</span><span class="p">)</span> <span class="o" style="font-weight: 600;">$</span></span>
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<td class="old_line diff-line-num old" data-linenumber="2259" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
2259
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<td class="new_line diff-line-num old" data-linenumber="2258" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
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<td class="line_content old" style="padding: inherit;" bgcolor="#fbe9eb"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>-<span id="LC2259" class="line" lang="haskell"> <span class="n" style="color: #333;">text</span> <span class="s" style="color: #d14;">"Covar can only appear in Refl and GRefl: "</span> <span class="o" style="font-weight: 600;"><+></span> <span class="n" style="color: #333;">ppr</span> <span class="n" style="color: #333;">co</span></span>
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<td class="old_line diff-line-num old" data-linenumber="2260" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
2260
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<td class="new_line diff-line-num old" data-linenumber="2258" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
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<td class="line_content old" style="padding: inherit;" bgcolor="#fbe9eb"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>-<span id="LC2260" class="line" lang="haskell"> <span class="c1" style="color: #998; font-style: italic;">-- See (FC6) in Note [ForAllCo] in GHC.Core.TyCo.Rep</span></span>
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<td class="old_line diff-line-num new" data-linenumber="2261" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
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<td class="new_line diff-line-num new" data-linenumber="2258" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
2258
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>+<span id="LC2258" class="line" lang="haskell"> <span class="kr" style="font-weight: 600;">do</span> <span class="p">{</span> <span class="n" style="color: #333;">lintL</span> <span class="p">(</span><span class="n" style="color: #333;">visL</span> <span class="o" style="font-weight: 600;">==</span> <span class="n" style="color: #333;">coreTyLamForAllTyFlag</span> <span class="o" style="font-weight: 600;">&&</span> <span class="n" style="color: #333;">visR</span> <span class="o" style="font-weight: 600;">==</span> <span class="n" style="color: #333;">coreTyLamForAllTyFlag</span><span class="p">)</span> <span class="o" style="font-weight: 600;">$</span></span>
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<td class="new_line diff-line-num new" data-linenumber="2259" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
2259
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>+<span id="LC2259" class="line" lang="haskell"> <span class="n" style="color: #333;">text</span> <span class="s" style="color: #d14;">"Invalid visibility flags in CoVar ForAllCo"</span> <span class="o" style="font-weight: 600;"><+></span> <span class="n" style="color: #333;">ppr</span> <span class="n" style="color: #333;">co</span></span>
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<td class="new_line diff-line-num new" data-linenumber="2260" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
2260
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>+<span id="LC2260" class="line" lang="haskell"> <span class="c1" style="color: #998; font-style: italic;">-- See (FC7) in Note [ForAllCo] in GHC.Core.TyCo.Rep</span></span>
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<td class="new_line diff-line-num new" data-linenumber="2261" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
2261
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>+<span id="LC2261" class="line" lang="haskell"> <span class="p">;</span> <span class="n" style="color: #333;">lintL</span> <span class="p">(</span><span class="n" style="color: #333;">almostDevoidCoVarOfCo</span> <span class="n" style="color: #333;">tcv</span> <span class="n" style="color: #333;">body_co</span><span class="p">)</span> <span class="o" style="font-weight: 600;">$</span></span>
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<td class="new_line diff-line-num new" data-linenumber="2262" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
2262
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>+<span id="LC2262" class="line" lang="haskell"> <span class="n" style="color: #333;">text</span> <span class="s" style="color: #d14;">"Covar can only appear in Refl and GRefl: "</span> <span class="o" style="font-weight: 600;"><+></span> <span class="n" style="color: #333;">ppr</span> <span class="n" style="color: #333;">co</span></span>
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<td class="new_line diff-line-num new" data-linenumber="2263" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
2263
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>+<span id="LC2263" class="line" lang="haskell"> <span class="c1" style="color: #998; font-style: italic;">-- See (FC6) in Note [ForAllCo] in GHC.Core.TyCo.Rep</span></span>
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2264
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>+<span id="LC2264" class="line" lang="haskell"> <span class="p">}</span></span>
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2261
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<td class="new_line diff-line-num" data-linenumber="2265" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
2265
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC2265" class="line" lang="haskell"></span>
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2262
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<td class="new_line diff-line-num" data-linenumber="2266" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
2266
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC2266" class="line" lang="haskell"> <span class="p">;</span> <span class="n" style="color: #333;">when</span> <span class="p">(</span><span class="n" style="color: #333;">body_role</span> <span class="o" style="font-weight: 600;">==</span> <span class="kt" style="color: #458; font-weight: 600;">Nominal</span><span class="p">)</span> <span class="o" style="font-weight: 600;">$</span></span>
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2263
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2267
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC2267" class="line" lang="haskell"> <span class="n" style="color: #333;">lintL</span> <span class="p">(</span><span class="n" style="color: #333;">visL</span> <span class="p">`</span><span class="n" style="color: #333;">eqForAllVis</span><span class="p">`</span> <span class="n" style="color: #333;">visR</span><span class="p">)</span> <span class="o" style="font-weight: 600;">$</span></span>
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<a href="https://gitlab.haskell.org/ghc/ghc/-/commit/275cafcb4f0045dde91c5ca1d0d564baf426afc4#578c7c3857d66d963736ff6742f3433a0e8d01b7"><strong style="font-weight: bold;">compiler/GHC/Core/TyCo/Rep.hs</strong></a>
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<td class="diff-line-num unfold js-unfold old_line" data-linenumber="878" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">...</td>
<td class="diff-line-num unfold js-unfold new_line" data-linenumber="878" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">...</td>
<td class="line_content match" style="color: rgba(31,30,36,0.24); padding: inherit;" bgcolor="#fbfafd">@@ -878,7 +878,7 @@ data Coercion</td>
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<td class="old_line diff-line-num" data-linenumber="878" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
878
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<td class="new_line diff-line-num" data-linenumber="878" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
878
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC878" class="line" lang="haskell"> <span class="p">{</span> <span class="n" style="color: #333;">fco_tcv</span> <span class="o" style="font-weight: 600;">::</span> <span class="kt" style="color: #458; font-weight: 600;">TyCoVar</span></span>
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<td class="old_line diff-line-num" data-linenumber="879" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
879
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<td class="new_line diff-line-num" data-linenumber="879" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
879
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC879" class="line" lang="haskell"> <span class="p">,</span> <span class="n" style="color: #333;">fco_visL</span> <span class="o" style="font-weight: 600;">::</span> <span class="o" style="font-weight: 600;">!</span><span class="kt" style="color: #458; font-weight: 600;">ForAllTyFlag</span> <span class="c1" style="color: #998; font-style: italic;">-- Vvisibility of coercionLKind</span></span>
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<td class="old_line diff-line-num" data-linenumber="880" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
880
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<td class="new_line diff-line-num" data-linenumber="880" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
880
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC880" class="line" lang="haskell"> <span class="p">,</span> <span class="n" style="color: #333;">fco_visR</span> <span class="o" style="font-weight: 600;">::</span> <span class="o" style="font-weight: 600;">!</span><span class="kt" style="color: #458; font-weight: 600;">ForAllTyFlag</span> <span class="c1" style="color: #998; font-style: italic;">-- Visibility of coercionRKind</span></span>
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<td class="old_line diff-line-num old" data-linenumber="881" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
881
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<td class="new_line diff-line-num old" data-linenumber="881" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
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<td class="line_content old" style="padding: inherit;" bgcolor="#fbe9eb"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>-<span id="LC881" class="line" lang="haskell"> <span class="c1" style="color: #998; font-style: italic;">-- See (FC7) of Note [For<span class="idiff left right deletion" style="background-color: #fac5cd;">a</span>llCo]</span></span>
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<td class="old_line diff-line-num new" data-linenumber="882" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
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<td class="new_line diff-line-num new" data-linenumber="881" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
881
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>+<span id="LC881" class="line" lang="haskell"> <span class="c1" style="color: #998; font-style: italic;">-- See (FC7) of Note [For<span class="idiff left right addition" style="background-color: #c7f0d2;">A</span>llCo]</span></span>
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<td class="old_line diff-line-num" data-linenumber="882" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
882
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<td class="new_line diff-line-num" data-linenumber="882" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
882
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC882" class="line" lang="haskell"> <span class="p">,</span> <span class="n" style="color: #333;">fco_kind</span> <span class="o" style="font-weight: 600;">::</span> <span class="kt" style="color: #458; font-weight: 600;">KindCoercion</span></span>
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883
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<td class="new_line diff-line-num" data-linenumber="883" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
883
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC883" class="line" lang="haskell"> <span class="p">,</span> <span class="n" style="color: #333;">fco_body</span> <span class="o" style="font-weight: 600;">::</span> <span class="kt" style="color: #458; font-weight: 600;">Coercion</span> <span class="p">}</span></span>
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884
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<td class="new_line diff-line-num" data-linenumber="884" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
884
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC884" class="line" lang="haskell"> <span class="c1" style="color: #998; font-style: italic;">-- ForAllCo :: _ -> N -> e -> e</span></span>
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<td class="diff-line-num unfold js-unfold old_line" data-linenumber="1260" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">...</td>
<td class="diff-line-num unfold js-unfold new_line" data-linenumber="1260" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">...</td>
<td class="line_content match" style="color: rgba(31,30,36,0.24); padding: inherit;" bgcolor="#fbfafd">@@ -1260,10 +1260,10 @@ Several things to note here</td>
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<td class="old_line diff-line-num" data-linenumber="1260" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
1260
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<td class="new_line diff-line-num" data-linenumber="1260" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
1260
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC1260" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> * Even if cv occurs in body_co, it is possible that cv does not occur in the kind</span></span>
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<td class="old_line diff-line-num" data-linenumber="1261" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
1261
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<td class="new_line diff-line-num" data-linenumber="1261" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
1261
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC1261" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> of body_co. Therefore the check in coercionKind is inevitable.</span></span>
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1262
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<td class="new_line diff-line-num" data-linenumber="1262" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
1262
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC1262" class="line" lang="haskell"></span>
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<td class="old_line diff-line-num old" data-linenumber="1263" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
1263
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<td class="new_line diff-line-num old" data-linenumber="1263" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
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<td class="line_content old" style="padding: inherit;" bgcolor="#fbe9eb"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>-<span id="LC1263" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">(FC6) <span class="idiff left deletion" style="background-color: #fac5cd;">Consider (ForAllCo cv kind_co body_co)</span> where <span class="idiff deletion" style="background-color: #fac5cd;">`</span>cv<span class="idiff deletion" style="background-color: #fac5cd;">`</span> is a coercion variable<span class="idiff right deletion" style="background-color: #fac5cd;">.</span></span></span>
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<td class="old_line diff-line-num old" data-linenumber="1264" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
1264
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<td class="new_line diff-line-num old" data-linenumber="1263" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
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<td class="line_content old" style="padding: inherit;" bgcolor="#fbe9eb"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>-<span id="LC1264" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> <span class="idiff left right deletion" style="background-color: #fac5cd;">W</span>e insist that `cv` appears only in positions that are erased. In fact we use</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1263" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
1263
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>+<span id="LC1263" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">(FC6) <span class="idiff left addition" style="background-color: #c7f0d2;">Invariant: in a ForAllCo</span> where <span class="idiff addition" style="background-color: #c7f0d2;">fco_t</span>cv is a coercion variable<span class="idiff right addition" style="background-color: #c7f0d2;">, `cv`,</span></span></span>
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<td class="new_line diff-line-num new" data-linenumber="1264" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
1264
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>+<span id="LC1264" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> <span class="idiff left right addition" style="background-color: #c7f0d2;">w</span>e insist that `cv` appears only in positions that are erased. In fact we use</span></span>
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1265
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<td class="new_line diff-line-num" data-linenumber="1265" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
1265
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC1265" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> a conservative approximation of this: we require that</span></span>
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1266
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<td class="new_line diff-line-num old" data-linenumber="1266" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
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<td class="line_content old" style="padding: inherit;" bgcolor="#fbe9eb"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>-<span id="LC1266" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> (almostDevoidCoVarOfCo cv body<span class="idiff left right deletion" style="background-color: #fac5cd;">_co</span>)</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1266" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
1266
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>+<span id="LC1266" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> (almostDevoidCoVarOfCo cv <span class="idiff left right addition" style="background-color: #c7f0d2;">fco_</span>body)</span></span>
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1267
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<td class="new_line diff-line-num" data-linenumber="1267" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
1267
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC1267" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> holds. This function checks that `cv` appers only within the type in a Refl</span></span>
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1268
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<td class="new_line diff-line-num" data-linenumber="1268" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
1268
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC1268" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> node and under a GRefl node (including in the Coercion stored in a GRefl).</span></span>
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1269
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<td class="new_line diff-line-num" data-linenumber="1269" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
1269
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC1269" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> It's possible other places are OK, too, but this is a safe approximation.</span></span>
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<td class="diff-line-num unfold js-unfold old_line" data-linenumber="1282" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">...</td>
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<td class="line_content match" style="color: rgba(31,30,36,0.24); padding: inherit;" bgcolor="#fbfafd">@@ -1282,7 +1282,7 @@ Several things to note here</td>
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<td class="old_line diff-line-num" data-linenumber="1282" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
1282
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<td class="new_line diff-line-num" data-linenumber="1282" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
1282
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC1282" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> proved that the problem does not occur with homogeneous equality, so this</span></span>
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1283
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<td class="new_line diff-line-num" data-linenumber="1283" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
1283
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC1283" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> check can be dropped once ~# is made to be homogeneous.</span></span>
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1284
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1284
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC1284" class="line" lang="haskell"></span>
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<td class="old_line diff-line-num old" data-linenumber="1285" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
1285
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<td class="new_line diff-line-num old" data-linenumber="1285" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
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<td class="line_content old" style="padding: inherit;" bgcolor="#fbe9eb"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>-<span id="LC1285" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">(FC7) In a ForAllCo, if fco_tcv is a CoVar, then</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1285" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
1285
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>+<span id="LC1285" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">(FC7) In<span class="idiff left right addition" style="background-color: #c7f0d2;">variant: in</span> a ForAllCo, if fco_tcv is a CoVar, then</span></span>
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1286
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<td class="new_line diff-line-num" data-linenumber="1286" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
1286
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC1286" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> fco_visL = fco_visR = coreTyLamForAllTyFlag</span></span>
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1287
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<td class="new_line diff-line-num" data-linenumber="1287" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
1287
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC1287" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> c.f. (FT2) in Note [ForAllTy]</span></span>
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC1288" class="line" lang="haskell"></span>
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<a href="https://gitlab.haskell.org/ghc/ghc/-/commit/275cafcb4f0045dde91c5ca1d0d564baf426afc4#7dc5395d86b92c5a2b05aa2e9c13c1635f051da8"><strong style="font-weight: bold;">docs/core-spec/core-spec.mng</strong></a>
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<td class="line_content match" style="color: rgba(31,30,36,0.24); padding: inherit;" bgcolor="#fbfafd">@@ -223,8 +223,8 @@ be a type function.</td>
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223
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC223" class="line" lang="tex">the payload in a <span class="k" style="font-weight: 600;">\texttt</span><span class="p">{</span>Refl<span class="p">}</span> must not be built with <span class="k" style="font-weight: 600;">\texttt</span><span class="p">{</span>CoercionTy<span class="p">}</span>.</span>
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<td class="old_line diff-line-num" data-linenumber="224" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
224
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<td class="new_line diff-line-num" data-linenumber="224" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
224
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC224" class="line" lang="tex"><span class="k" style="font-weight: 600;">\item</span> If <span class="p">$</span><span class="o" style="font-weight: 600;">[[</span><span class="nb" style="color: #0086b3;">forall z: h .g</span><span class="o" style="font-weight: 600;">]]</span><span class="p">$</span> is a polymorphic coercion over a coercion variable</span>
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<td class="old_line diff-line-num" data-linenumber="225" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
225
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<td class="new_line diff-line-num" data-linenumber="225" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
225
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC225" class="line" lang="tex"> (i.e. <span class="p">$</span><span class="o" style="font-weight: 600;">[[</span><span class="nb" style="color: #0086b3;">z</span><span class="o" style="font-weight: 600;">]]</span><span class="p">$</span> is a coercion variable), then <span class="p">$</span><span class="o" style="font-weight: 600;">[[</span><span class="nb" style="color: #0086b3;">z</span><span class="o" style="font-weight: 600;">]]</span><span class="p">$</span> can only appear in</span>
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<td class="old_line diff-line-num old" data-linenumber="226" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
226
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<td class="new_line diff-line-num old" data-linenumber="226" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
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<td class="line_content old" style="padding: inherit;" bgcolor="#fbe9eb"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>-<span id="LC226" class="line" lang="tex"> <span class="k" style="font-weight: 600;">\texttt</span><span class="p">{</span>Refl<span class="p">}</span> and <span class="k" style="font-weight: 600;">\texttt</span><span class="p">{</span>GRefl<span class="p">}</span> in <span class="p">$</span><span class="o" style="font-weight: 600;">[[</span><span class="nb" style="color: #0086b3;">g</span><span class="o" style="font-weight: 600;">]]</span><span class="p">$</span>. See <span class="k" style="font-weight: 600;">\texttt</span><span class="p">{</span><span class="idiff left right deletion" style="background-color: #fac5cd;">Note [Unused coercion</span></span>
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<td class="old_line diff-line-num old" data-linenumber="227" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
227
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<td class="new_line diff-line-num old" data-linenumber="226" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
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<td class="line_content old" style="padding: inherit;" bgcolor="#fbe9eb"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>-<span id="LC227" class="line" lang="tex"> <span class="idiff left deletion" style="background-color: #fac5cd;"> variable in ForAllCo] </span>in <span class="k" style="font-weight: 600;">\ghcfile</span><span class="p">{</span>GHC.Core.<span class="idiff right deletion" style="background-color: #fac5cd;">Coercion</span><span class="p">}}</span>.</span>
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<td class="old_line diff-line-num new" data-linenumber="228" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
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<td class="new_line diff-line-num new" data-linenumber="226" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
226
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>+<span id="LC226" class="line" lang="tex"> <span class="k" style="font-weight: 600;">\texttt</span><span class="p">{</span>Refl<span class="p">}</span> and <span class="k" style="font-weight: 600;">\texttt</span><span class="p">{</span>GRefl<span class="p">}</span> in <span class="p">$</span><span class="o" style="font-weight: 600;">[[</span><span class="nb" style="color: #0086b3;">g</span><span class="o" style="font-weight: 600;">]]</span><span class="p">$</span>. See <span class="k" style="font-weight: 600;">\texttt</span><span class="p">{</span><span class="idiff left right addition" style="background-color: #c7f0d2;">(FC6) in Note [ForAllCo]</span></span>
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<td class="old_line diff-line-num new" data-linenumber="228" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
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<td class="new_line diff-line-num new" data-linenumber="227" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
227
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'>+<span id="LC227" class="line" lang="tex"> in <span class="k" style="font-weight: 600;">\ghcfile</span><span class="p">{</span>GHC.Core.<span class="idiff left right addition" style="background-color: #c7f0d2;">TyCon.Rep</span><span class="p">}}</span>.</span>
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<td class="old_line diff-line-num" data-linenumber="228" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
228
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<td class="new_line diff-line-num" data-linenumber="228" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
228
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC228" class="line" lang="tex"><span class="k" style="font-weight: 600;">\item</span> Prefer <span class="p">$</span><span class="o" style="font-weight: 600;">[[</span><span class="nb" style="color: #0086b3;">g</span><span class="m" style="color: #099;">1</span><span class="nb" style="color: #0086b3;"> </span><span class="o" style="font-weight: 600;">-</span><span class="nb" style="color: #0086b3;">></span><span class="p">_</span><span class="nb" style="color: #0086b3;">R g</span><span class="m" style="color: #099;">2</span><span class="o" style="font-weight: 600;">]]</span><span class="p">$</span> over <span class="p">$</span><span class="o" style="font-weight: 600;">[[(-</span><span class="nb" style="color: #0086b3;">></span><span class="o" style="font-weight: 600;">)</span><span class="p">_</span><span class="nb" style="color: #0086b3;">R g</span><span class="m" style="color: #099;">1</span><span class="nb" style="color: #0086b3;"> g</span><span class="m" style="color: #099;">2</span><span class="o" style="font-weight: 600;">]]</span><span class="p">$</span>; that is, we use <span class="k" style="font-weight: 600;">\ctor</span><span class="p">{</span>FunCo<span class="p">}</span>,</span>
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<td class="old_line diff-line-num" data-linenumber="229" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
229
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<td class="new_line diff-line-num" data-linenumber="229" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
229
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC229" class="line" lang="tex">never <span class="k" style="font-weight: 600;">\ctor</span><span class="p">{</span>TyConAppCo<span class="p">}</span>, for coercions over saturated uses of <span class="p">$</span><span class="o" style="font-weight: 600;">[[-</span><span class="nb" style="color: #0086b3;">></span><span class="o" style="font-weight: 600;">]]</span><span class="p">$</span>.</span>
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<td class="old_line diff-line-num" data-linenumber="230" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
230
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<td class="new_line diff-line-num" data-linenumber="230" style="width: 35px; color: rgba(31,30,36,0.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
230
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;'> <span id="LC230" class="line" lang="tex"><span class="nt" style="color: #000080;">\end{itemize}</span></span>
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