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Vladislav Zavialov pushed to branch wip/int-index/visibility-check at <a href="https://gitlab.haskell.org/ghc/ghc" style="color: #1068bf;">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/60cf227ee77c7bbf18e53fccb593368882ad3b2e" style="color: #1068bf;">60cf227e</a></strong>
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<span> by Ryan Scott </span> <i> at 2023-02-05T23:32:47+00:00 </i>
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<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Apply 7 suggestion(s) to 2 file(s)</pre>
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2 changed files:
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compiler/GHC/Core/TyCo/Compare.hs
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compiler/GHC/Tc/Utils/TcMType.hs
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Changes:
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<a href="https://gitlab.haskell.org/ghc/ghc/-/commit/60cf227ee77c7bbf18e53fccb593368882ad3b2e#f12e69f869289252159b0af74c2a0b72b429ab3a" style="color: #1068bf;"><strong style="font-weight: bold;">compiler/GHC/Core/TyCo/Compare.hs</strong></a>
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<td class="diff-line-num unfold js-unfold old_line" data-linenumber="246" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">...</td>
<td class="diff-line-num unfold js-unfold new_line" data-linenumber="246" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">...</td>
<td class="line_content match" style="color: rgba(0,0,0,0.3); padding: inherit;" bgcolor="#fafafa">@@ -246,7 +246,7 @@ When we compare (ForAllTy (Bndr tv1 vis1) ty1)</td>
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<td class="old_line diff-line-num" data-linenumber="246" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
246
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<td class="new_line diff-line-num" data-linenumber="246" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
246
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC246" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">what should we do about `vis1` vs `vis2`?</span></span>
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<td class="old_line diff-line-num" data-linenumber="247" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
247
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<td class="new_line diff-line-num" data-linenumber="247" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
247
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC247" class="line" lang="haskell"></span>
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<td class="old_line diff-line-num" data-linenumber="248" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
248
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<td class="new_line diff-line-num" data-linenumber="248" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
248
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC248" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">One option is to take those flags into account and check (vis1==vis2).</span></span>
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<td class="old_line diff-line-num old" data-linenumber="249" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
249
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<td class="new_line diff-line-num old" data-linenumber="249" style="width: 35px; color: rgba(0,0,0,0.3); 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: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>-<span id="LC249" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">But in Core visibilit<span class="idiff left deletion" style="background-color: #fac5cd;">y</span> of forall-bound variables ha<span class="idiff right deletion" style="background-color: #fac5cd;">s</span> no meaning,</span></span>
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<td class="old_line diff-line-num new" data-linenumber="250" style="width: 35px; color: rgba(0,0,0,0.3); 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="249" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
249
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>+<span id="LC249" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">But in Core<span class="idiff left addition" style="background-color: #c7f0d2;">, the</span> visibilit<span class="idiff addition" style="background-color: #c7f0d2;">ies</span> of forall-bound variables ha<span class="idiff right addition" style="background-color: #c7f0d2;">ve</span> no meaning,</span></span>
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250
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<td class="new_line diff-line-num" data-linenumber="250" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
250
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC250" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">as type abstraction and type application are always explicit.</span></span>
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<td class="old_line diff-line-num" data-linenumber="251" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
251
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<td class="new_line diff-line-num" data-linenumber="251" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
251
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC251" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">Going to great lengths to carry them around is counterproductive,</span></span>
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<td class="old_line diff-line-num" data-linenumber="252" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
252
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<td class="new_line diff-line-num" data-linenumber="252" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
252
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC252" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">but not going far enough may lead to Core Lint errors (#22762).</span></span>
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<td class="diff-line-num unfold js-unfold old_line" data-linenumber="255" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">...</td>
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<td class="line_content match" style="color: rgba(0,0,0,0.3); padding: inherit;" bgcolor="#fafafa">@@ -255,13 +255,13 @@ The other option (the one we take) is to ignore those flags.</td>
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<td class="new_line diff-line-num" data-linenumber="255" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC255" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">Neither the name of a forall-bound variable nor its visibility flag</span></span>
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<td class="old_line diff-line-num" data-linenumber="256" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC256" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">affect GHC's notion of type equality.</span></span>
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257
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC257" class="line" lang="haskell"></span>
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<td class="old_line diff-line-num old" data-linenumber="258" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
258
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<td class="new_line diff-line-num old" data-linenumber="258" style="width: 35px; color: rgba(0,0,0,0.3); 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: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>-<span id="LC258" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">That said, <span class="idiff left deletion" style="background-color: #fac5cd;">in user-written programs</span> visibilit<span class="idiff deletion" style="background-color: #fac5cd;">y</span> of foralls do<span class="idiff right deletion" style="background-color: #fac5cd;">es</span> matter</span></span>
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<td class="old_line diff-line-num old" data-linenumber="259" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
259
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<td class="new_line diff-line-num old" data-linenumber="258" style="width: 35px; color: rgba(0,0,0,0.3); 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: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>-<span id="LC259" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">a great deal. For example, if we unify tv := T, where</span></span>
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<td class="old_line diff-line-num new" data-linenumber="260" style="width: 35px; color: rgba(0,0,0,0.3); 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="258" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
258
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>+<span id="LC258" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">That said, <span class="idiff left addition" style="background-color: #c7f0d2;">the</span> visibilit<span class="idiff right addition" style="background-color: #c7f0d2;">ies</span> of foralls do matter</span></span>
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259
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>+<span id="LC259" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">a great deal<span class="idiff left right addition" style="background-color: #c7f0d2;"> in user-written programs</span>. For example, if we unify tv := T, where</span></span>
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260
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<td class="new_line diff-line-num" data-linenumber="260" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
260
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC260" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> tv :: forall k. k -> Type</span></span>
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<td class="old_line diff-line-num" data-linenumber="261" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
261
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<td class="new_line diff-line-num" data-linenumber="261" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
261
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC261" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> T :: forall k -> k -> Type</span></span>
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<td class="old_line diff-line-num old" data-linenumber="262" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
262
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<td class="new_line diff-line-num old" data-linenumber="262" style="width: 35px; color: rgba(0,0,0,0.3); 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: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>-<span id="LC262" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">then the user can<span class="idiff left right deletion" style="background-color: #fac5cd;"> </span>not substitute `T Maybe` for `tv Maybe` in their program</span></span>
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<td class="old_line diff-line-num new" data-linenumber="263" style="width: 35px; color: rgba(0,0,0,0.3); 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="262" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
262
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>+<span id="LC262" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">then the user cannot substitute `T Maybe` for `tv Maybe` in their program</span></span>
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<td class="old_line diff-line-num" data-linenumber="263" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
263
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<td class="new_line diff-line-num" data-linenumber="263" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
263
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC263" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">by hand. They'd have to write `T (Type -> Type) Maybe` instead.</span></span>
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<td class="old_line diff-line-num old" data-linenumber="264" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
264
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<td class="new_line diff-line-num old" data-linenumber="264" style="width: 35px; color: rgba(0,0,0,0.3); 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: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>-<span id="LC264" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">This entails loss referential transparency. We solve this issue by</span></span>
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<td class="old_line diff-line-num new" data-linenumber="265" style="width: 35px; color: rgba(0,0,0,0.3); 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="264" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
264
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>+<span id="LC264" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">This entails <span class="idiff left addition" style="background-color: #c7f0d2;">a </span>loss <span class="idiff right addition" style="background-color: #c7f0d2;">of </span>referential transparency. We solve this issue by</span></span>
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<td class="old_line diff-line-num" data-linenumber="265" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
265
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<td class="new_line diff-line-num" data-linenumber="265" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
265
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC265" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">checking the flags *outside* the equality relation. To that end,</span></span>
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<td class="old_line diff-line-num" data-linenumber="266" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
266
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<td class="new_line diff-line-num" data-linenumber="266" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
266
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC266" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">there are two ad-hoc checks:</span></span>
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267
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<td class="new_line diff-line-num" data-linenumber="267" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
267
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC267" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> * checkEqForallVis (in checking mode)</span></span>
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<td class="diff-line-num unfold js-unfold old_line" data-linenumber="271" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">...</td>
<td class="diff-line-num unfold js-unfold new_line" data-linenumber="271" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">...</td>
<td class="line_content match" style="color: rgba(0,0,0,0.3); padding: inherit;" bgcolor="#fafafa">@@ -271,8 +271,7 @@ These checks use `eqForAllVis` to compare the `ForAllTyFlag`s.</td>
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<td class="old_line diff-line-num" data-linenumber="271" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
271
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<td class="new_line diff-line-num" data-linenumber="271" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
271
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC271" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">But should we perhaps use (==) instead?</span></span>
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<td class="old_line diff-line-num" data-linenumber="272" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
272
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<td class="new_line diff-line-num" data-linenumber="272" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
272
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC272" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">Do we only care about visibility (Required vs Invisible)</span></span>
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<td class="old_line diff-line-num" data-linenumber="273" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
273
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<td class="new_line diff-line-num" data-linenumber="273" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
273
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC273" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">or do we also care about specificity (Specified vs Inferred)?</span></span>
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<td class="old_line diff-line-num old" data-linenumber="274" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
274
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<td class="new_line diff-line-num old" data-linenumber="274" style="width: 35px; color: rgba(0,0,0,0.3); 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: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>-<span id="LC274" class="line" lang="haskell"></span>
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<td class="old_line diff-line-num old" data-linenumber="275" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
275
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<td class="new_line diff-line-num old" data-linenumber="274" style="width: 35px; color: rgba(0,0,0,0.3); 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: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>-<span id="LC275" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">Should GHC type-check the following program (adapted from #15740)?</span></span>
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<td class="old_line diff-line-num new" data-linenumber="276" style="width: 35px; color: rgba(0,0,0,0.3); 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="274" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
274
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>+<span id="LC274" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">For example, should GHC type-check the following program (adapted from #15740)?</span></span>
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276
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<td class="new_line diff-line-num" data-linenumber="275" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
275
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC275" class="line" lang="haskell"></span>
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<td class="old_line diff-line-num" data-linenumber="277" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
277
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<td class="new_line diff-line-num" data-linenumber="276" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
276
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC276" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> {-# LANGUAGE PolyKinds, ... #-}</span></span>
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC277" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> data D a</span></span>
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<a href="https://gitlab.haskell.org/ghc/ghc/-/commit/60cf227ee77c7bbf18e53fccb593368882ad3b2e#94c96afe1bb3b771ffbcfeeca34ce43ebbe76ccb" style="color: #1068bf;"><strong style="font-weight: bold;">compiler/GHC/Tc/Utils/TcMType.hs</strong></a>
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<td class="diff-line-num unfold js-unfold new_line" data-linenumber="614" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">...</td>
<td class="line_content match" style="color: rgba(0,0,0,0.3); padding: inherit;" bgcolor="#fafafa">@@ -614,7 +614,7 @@ tc_infer mb_frr tc_check</td>
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614
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC614" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">* *</span></span>
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615
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC615" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">********************************************************************* -}</span></span>
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616
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616
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC616" class="line" lang="haskell"></span>
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<td class="old_line diff-line-num old" data-linenumber="617" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
617
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<td class="new_line diff-line-num old" data-linenumber="617" style="width: 35px; color: rgba(0,0,0,0.3); 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: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>-<span id="LC617" class="line" lang="haskell"><span class="c1" style="color: #998; font-style: italic;">-- Check if two presumably equal types actually differ in visibility</span></span>
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<td class="old_line diff-line-num new" data-linenumber="618" style="width: 35px; color: rgba(0,0,0,0.3); 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="617" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
617
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>+<span id="LC617" class="line" lang="haskell"><span class="c1" style="color: #998; font-style: italic;">-- Check if two presumably equal types actually differ in <span class="idiff left right addition" style="background-color: #c7f0d2;">the </span>visibility</span></span>
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618
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<td class="new_line diff-line-num" data-linenumber="618" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
618
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC618" class="line" lang="haskell"><span class="c1" style="color: #998; font-style: italic;">-- of their foralls. Example (from #18863):</span></span>
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619
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619
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC619" class="line" lang="haskell"><span class="c1" style="color: #998; font-style: italic;">--</span></span>
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620
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC620" class="line" lang="haskell"><span class="c1" style="color: #998; font-style: italic;">-- type IDa :: forall i -> i -> Type</span></span>
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<td class="diff-line-num unfold js-unfold old_line" data-linenumber="630" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">...</td>
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<td class="line_content match" style="color: rgba(0,0,0,0.3); padding: inherit;" bgcolor="#fafafa">@@ -630,7 +630,7 @@ checkEqForallVis ty1 (Check ty2) =</td>
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630
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630
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC630" class="line" lang="haskell"> <span class="n" style="color: #333;">addErr</span> <span class="o" style="font-weight: 600;">$</span> <span class="kt" style="color: #458; font-weight: 600;">TcRnIncompatibleForallVisibility</span> <span class="n" style="color: #333;">ty1</span> <span class="n" style="color: #333;">ty2</span></span>
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631
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631
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC631" class="line" lang="haskell"></span>
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632
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<td class="new_line diff-line-num" data-linenumber="632" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
632
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC632" class="line" lang="haskell"><span class="c1" style="color: #998; font-style: italic;">-- Structurally match two presumably equal types, checking that all pairs of</span></span>
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633
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<td class="new_line diff-line-num old" data-linenumber="633" style="width: 35px; color: rgba(0,0,0,0.3); 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: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>-<span id="LC633" class="line" lang="haskell"><span class="c1" style="color: #998; font-style: italic;">-- foralls have equal visibilit<span class="idiff left right deletion" style="background-color: #fac5cd;">y</span>.</span></span>
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<td class="new_line diff-line-num new" data-linenumber="633" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
633
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<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'>+<span id="LC633" class="line" lang="haskell"><span class="c1" style="color: #998; font-style: italic;">-- foralls have equal visibilit<span class="idiff left right addition" style="background-color: #c7f0d2;">ies</span>.</span></span>
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634
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634
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC634" class="line" lang="haskell"><span class="c1" style="color: #998; font-style: italic;">--</span></span>
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635
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<td class="new_line diff-line-num" data-linenumber="635" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
635
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC635" class="line" lang="haskell"><span class="c1" style="color: #998; font-style: italic;">-- See Note [Presumably equal types]</span></span>
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636
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<td class="new_line diff-line-num" data-linenumber="636" style="width: 35px; color: rgba(0,0,0,0.3); border-right-width: 1px; border-right-color: #f0f0f0; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fafafa">
636
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "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 #dbdbdb;'> <span id="LC636" class="line" lang="haskell"><span class="n" style="color: #333;">tcEqForallVis</span> <span class="o" style="font-weight: 600;">::</span> <span class="kt" style="color: #458; font-weight: 600;">Type</span> <span class="o" style="font-weight: 600;">-></span> <span class="kt" style="color: #458; font-weight: 600;">Type</span> <span class="o" style="font-weight: 600;">-></span> <span class="kt" style="color: #458; font-weight: 600;">Bool</span></span>
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