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Vladislav Zavialov pushed to branch wip/int-index/term-capture 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/31a4bc49f1d27bc34af613256838ffc8e3f7e20b">31a4bc49</a></strong>
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<span> by Vladislav Zavialov </span> <i> at 2023-11-23T16:36:22+03:00 </i>
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1 changed file:
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compiler/GHC/Rename/Env.hs
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Changes:
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<a href="https://gitlab.haskell.org/ghc/ghc/-/commit/31a4bc49f1d27bc34af613256838ffc8e3f7e20b#86d694037d496c511e28b2c09c8410f67dc19596"><strong style="font-weight: bold;">compiler/GHC/Rename/Env.hs</strong></a>
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<td class="diff-line-num unfold js-unfold new_line" data-linenumber="1157" 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">@@ -1157,11 +1157,28 @@ that up instead. If that succeeds, use it.</td>
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<td class="old_line diff-line-num" data-linenumber="1157" 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">
1157
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<td class="new_line diff-line-num" data-linenumber="1157" 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">
1157
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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="LC1157" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> A side effect of demotion is that the renamer also allows actual</span></span>
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<td class="old_line diff-line-num" data-linenumber="1158" 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">
1158
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<td class="new_line diff-line-num" data-linenumber="1158" 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">
1158
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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="LC1158" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> term variables to occur at the type level:</span></span>
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<td class="old_line diff-line-num" data-linenumber="1159" 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">
1159
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<td class="new_line diff-line-num" data-linenumber="1159" 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">
1159
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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="LC1159" class="line" lang="haskell"></span>
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<td class="old_line diff-line-num old" data-linenumber="1160" 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">
1160
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<td class="new_line diff-line-num old" data-linenumber="1160" 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: var(--default-mono-font, "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="LC1160" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> t = True</span></span>
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<td class="old_line diff-line-num old" data-linenumber="1161" 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">
1161
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<td class="new_line diff-line-num old" data-linenumber="1160" 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">
</td>
<td class="line_content old" style="padding: inherit;" bgcolor="#fbe9eb"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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="LC1161" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> x = Proxy @t -- Not good!</span></span>
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<td class="old_line diff-line-num old" data-linenumber="1162" 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">
1162
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<td class="new_line diff-line-num old" data-linenumber="1160" 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: var(--default-mono-font, "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="LC1162" class="line" lang="haskell"></span>
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<td class="old_line diff-line-num old" data-linenumber="1163" 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">
1163
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<td class="new_line diff-line-num old" data-linenumber="1160" 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: var(--default-mono-font, "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="LC1163" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> GHC doesn't promote arbitrary terms to types. This is rejected in the type</span></span>
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<td class="old_line diff-line-num old" data-linenumber="1164" 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">
1164
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<td class="new_line diff-line-num old" data-linenumber="1160" 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: var(--default-mono-font, "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="LC1164" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> checker via tcAddTermVarPlaceholders.</span></span>
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<td class="old_line diff-line-num new" data-linenumber="1165" 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="1160" 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">
1160
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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: var(--default-mono-font, "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="LC1160" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> t = True -- Ordinary term-level binding</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1161" 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">
1161
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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: var(--default-mono-font, "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="LC1161" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> x = Proxy @t -- (1) Bad usage in a HsExpr</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1162" 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">
1162
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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: var(--default-mono-font, "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="LC1162" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> type T = t -- (2) Bad usage in a TyClDecl</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1163" 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">
1163
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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: var(--default-mono-font, "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="LC1163" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> f :: t -> t -- (3) Bad usage in a SigDecl</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1164" 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">
1164
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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: var(--default-mono-font, "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="LC1164" class="line" lang="haskell"></span>
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<td class="new_line diff-line-num new" data-linenumber="1165" 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">
1165
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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: var(--default-mono-font, "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="LC1165" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> GHC doesn't promote arbitrary terms to types, so the type checker has to</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1166" 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">
1166
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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: var(--default-mono-font, "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="LC1166" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> reject the uses of `t` shown above. This is achieved as follows:</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1167" 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">
1167
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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: var(--default-mono-font, "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="LC1167" class="line" lang="haskell"></span>
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<td class="old_line diff-line-num new" data-linenumber="1165" 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="1168" 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">
1168
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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: var(--default-mono-font, "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="LC1168" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> * In the HsExpr example (1) the type checker looks up `t` in the environment,</span></span>
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<td class="old_line diff-line-num new" data-linenumber="1165" 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="1169" 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">
1169
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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: var(--default-mono-font, "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="LC1169" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> finds `ATcId`, and generates a `TermVariablePE` promotion error.</span></span>
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<td class="old_line diff-line-num new" data-linenumber="1165" 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="1170" 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">
1170
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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: var(--default-mono-font, "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="LC1170" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> See the following clause in `tcTyVar`:</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1171" 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">
1171
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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: var(--default-mono-font, "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="LC1171" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> ATcId{} -> promotionErr name TermVariablePE</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1172" 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">
1172
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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: var(--default-mono-font, "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="LC1172" class="line" lang="haskell"></span>
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<td class="old_line diff-line-num new" data-linenumber="1165" 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="1173" 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">
1173
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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: var(--default-mono-font, "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="LC1173" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> * In the TyClDecl example (2) and SigDecl example (3), we don't have `ATcId`</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1174" 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">
1174
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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: var(--default-mono-font, "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="LC1174" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> in the environment just yet, because type declarations and signatures are</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1175" 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">
1175
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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: var(--default-mono-font, "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="LC1175" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> type-checked /before/ term-level bindings.</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1176" 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">
1176
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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: var(--default-mono-font, "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="LC1176" class="line" lang="haskell"></span>
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<td class="new_line diff-line-num new" data-linenumber="1177" 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">
1177
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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: var(--default-mono-font, "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="LC1177" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> To report a proper user-facing error message instead of a GHC panic,</span></span>
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<td class="old_line diff-line-num new" data-linenumber="1165" 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="1178" 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">
1178
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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: var(--default-mono-font, "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="LC1178" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> we proactively populate the environment with the `TermVariablePE` promotion</span></span>
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<td class="old_line diff-line-num new" data-linenumber="1165" 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="1179" 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">
1179
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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: var(--default-mono-font, "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="LC1179" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> error, one for each term variable in the current HsGroup (at the top level)</span></span>
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<td class="new_line diff-line-num new" data-linenumber="1180" 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">
1180
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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: var(--default-mono-font, "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="LC1180" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> or in the current HsValBinds (at the level of local let/where bindings).</span></span>
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<td class="old_line diff-line-num new" data-linenumber="1165" 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="1181" 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">
1181
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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: var(--default-mono-font, "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="LC1181" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> This is done with tactically placed calls to `tcAddTermVarPlaceholders`.</span></span>
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1165
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<td class="new_line diff-line-num" data-linenumber="1182" 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">
1182
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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="LC1182" class="line" lang="haskell"></span>
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<td class="old_line diff-line-num" data-linenumber="1166" 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">
1166
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<td class="new_line diff-line-num" data-linenumber="1183" 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">
1183
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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="LC1183" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;">(W2) Wrinkle 2</span></span>
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<td class="old_line diff-line-num" data-linenumber="1167" 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">
1167
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<td class="new_line diff-line-num" data-linenumber="1184" 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">
1184
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<td class="line_content" style="padding: inherit;"><pre style='display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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="LC1184" class="line" lang="haskell"><span class="cm" style="color: #998; font-style: italic;"> Only unqualified variable names are demoted, e.g. `f` but not `M.f`.</span></span>
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