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Marge Bot pushed to branch master 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/b69461a06166d2b1c600df87b87656d09122fb7c" style="color: #1068bf;">b69461a0</a></strong>
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<span> by Jason Shipman </span> <i> at 2023-01-30T21:21:50-05:00 </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;'>User's guide: Clarify overlapping instance candidate elimination
This commit updates the user's guide section on overlapping instance candidate
elimination to use "or" verbiage instead of "either/or" in regards to the
current pair of candidates' being overlappable or overlapping. "Either IX is
overlappable, or IY is overlapping" can cause confusion as it suggests "Either
IX is overlappable, or IY is overlapping, but not both".
This was initially discussed on this Discourse topic:
https://discourse.haskell.org/t/clarification-on-overlapping-instance-candidate-elimination/5677
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1 changed file:
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<a href="#ed75822e0b6142f196a6abeb623c7669d31b4711" style="color: #1068bf;">
docs/users_guide/exts/instances.rst
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Changes:
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<li id="ed75822e0b6142f196a6abeb623c7669d31b4711">
<a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b69461a06166d2b1c600df87b87656d09122fb7c#ed75822e0b6142f196a6abeb623c7669d31b4711" style="color: #1068bf;"><strong style="font-weight: bold;">docs/users_guide/exts/instances.rst</strong></a>
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<td class="diff-line-num unfold js-unfold old_line" data-linenumber="486" 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="486" 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">@@ -486,8 +486,8 @@ like this:</td>
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<td class="old_line diff-line-num" data-linenumber="486" 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">
486
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<td class="new_line diff-line-num" data-linenumber="486" 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">
486
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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="LC486" class="line" lang="plaintext"> - :math:`IY` is strictly more specific than :math:`IX`. That</span>
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<td class="old_line diff-line-num" data-linenumber="487" 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">
487
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<td class="new_line diff-line-num" data-linenumber="487" 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">
487
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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="LC487" class="line" lang="plaintext"> is, :math:`IY` is a substitution instance of :math:`IX` but not vice versa.</span>
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<td class="old_line diff-line-num" data-linenumber="488" 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">
488
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<td class="new_line diff-line-num" data-linenumber="488" 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">
488
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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="LC488" class="line" lang="plaintext"></span>
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<td class="old_line diff-line-num old" data-linenumber="489" 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">
489
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<td class="new_line diff-line-num old" data-linenumber="489" 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="LC489" class="line" lang="plaintext"> - <span class="idiff left deletion" style="background-color: #fac5cd;">Either </span>:math:`IX` is *overlappable*<span class="idiff right deletion" style="background-color: #fac5cd;">,</span> or :math:`IY` is *overlapping*. (This</span>
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<td class="old_line diff-line-num old" data-linenumber="490" 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">
490
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<td class="new_line diff-line-num old" data-linenumber="489" 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="LC490" class="line" lang="plaintext"> "<span class="idiff left deletion" style="background-color: #fac5cd;">either/</span>or" design, rather than a "<span class="idiff right deletion" style="background-color: #fac5cd;">both/</span>and" design, allow a</span>
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<td class="old_line diff-line-num new" data-linenumber="491" 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="489" 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">
489
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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="LC489" class="line" lang="plaintext"> - :math:`IX` is *overlappable* or :math:`IY` is *overlapping*. (This</span>
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<td class="old_line diff-line-num new" data-linenumber="491" 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="490" 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">
490
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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="LC490" class="line" lang="plaintext"> "or" design, rather than a<span class="idiff left addition" style="background-color: #c7f0d2;">n</span> "and" design, allow<span class="idiff right addition" style="background-color: #c7f0d2;">s</span> a</span>
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<td class="old_line diff-line-num" data-linenumber="491" 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">
491
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<td class="new_line diff-line-num" data-linenumber="491" 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">
491
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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="LC491" class="line" lang="plaintext"> client to deliberately override an instance from a library,</span>
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<td class="old_line diff-line-num" data-linenumber="492" 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">
492
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<td class="new_line diff-line-num" data-linenumber="492" 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">
492
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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="LC492" class="line" lang="plaintext"> without requiring a change to the library.)</span>
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493
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493
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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="LC493" class="line" lang="plaintext"></span>
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