Set deny-warnings for compiler/library/tools profiles to false

Author: WaffleLapkin

bootstrap.example.toml

@@ -826,9 +826,18 @@
 # in the sysroot. It is required for running nvptx tests.
 #rust.llvm-bitcode-linker = false
 
-# Whether to deny warnings in crates. Set to `false` to avoid
-# error: warnings are denied by `build.warnings` configuration
-#rust.deny-warnings = true
+# Whether to deny warnings in crates.
+#
+# Set to `true` to fail the build if there are warnings in crates,
+# to not accidentally miss warnings in long build output.
+#
+# Set to `false` to avoid "error: warnings are denied by `build.warnings` configuration"
+# and have easier time iterating on your changes.
+#
+# This is set to `true` by default for the `dist` profile and to `false` otherwise.
+#
+# Note that CI denies warnings.
+#rust.deny-warnings = false
 
 # Print backtrace on internal compiler errors during bootstrap
 #rust.backtrace-on-ice = false

src/bootstrap/defaults/bootstrap.compiler.toml

@@ -25,6 +25,8 @@ frame-pointers = true
 # e.g. check that it builds locally and check the baseline behavior of a
 # compiler built from latest `main` commit.
 download-rustc = false
+# Don't fail compilation when there are warnings.
+deny-warnings = false
 
 [llvm]
 # Having this set to true disrupts compiler development workflows for people who use `llvm.download-ci-llvm = true`

src/bootstrap/defaults/bootstrap.dist.toml

@@ -26,6 +26,8 @@ download-rustc = false
 llvm-bitcode-linker = true
 # Required to make builds reproducible.
 remap-debuginfo = true
+# Fail compilation when there are warnings.
+deny-warnings = true
 
 [dist]
 # Use better compression when preparing tarballs.

src/bootstrap/defaults/bootstrap.library.toml

@@ -14,6 +14,8 @@ lto = "off"
 # library development by skipping compiler builds.
 # FIXME: download-rustc is currently broken: https://github.com/rust-lang/rust/issues/142505
 download-rustc = false
+# Don't fail compilation when there are warnings.
+deny-warnings = false
 
 [llvm]
 # Will download LLVM from CI if available on your platform.

src/bootstrap/defaults/bootstrap.tools.toml

@@ -6,6 +6,8 @@ incremental = true
 # Most commonly, tools contributors do not need to modify the compiler, so
 # downloading a CI rustc is a good default for tools profile.
 download-rustc = "if-unchanged"
+# Don't fail compilation when there are warnings.
+deny-warnings = false
 
 [build]
 # cargo and clippy tests don't pass on stage 1

src/bootstrap/src/utils/change_tracker.rs

@@ -621,4 +621,9 @@ pub const CONFIG_CHANGE_HISTORY: &[ChangeInfo] = &[
         severity: ChangeSeverity::Info,
         summary: "`x.py` stopped accepting partial argument names. Use full names to avoid errors.",
     },
+    ChangeInfo {
+        change_id: 124439,
+        severity: ChangeSeverity::Info,
+        summary: "Default for `rust.deny-warnings` on `compiler`, `library` and `tools` profiles changed to `false`",
+    },
 ];