respond to review feedback: mainly eliminate as many conversions as possible...

- ... when creating diagnostics in rustc_metadata
-  use the error_code! macro
- pass macro output to diag.code()
- use fluent from within manual implementation of SessionDiagnostic
- emit the untested errors in case they occur in the wild
- stop panicking in the probably-not-dead code, add fixme to write test

Author: CleanCut

Cargo.lock

@@ -3514,6 +3514,7 @@ dependencies = [
  "rustc_macros",
  "rustc_serialize",
  "rustc_span",
+ "rustc_target",
  "serde",
  "serde_json",
  "termcolor",

compiler/rustc_error_messages/locales/en-US/metadata.ftl

@@ -225,3 +225,33 @@ metadata_cannot_find_crate =
 
 metadata_no_dylib_plugin =
     plugin `{$crate_name}` only found in rlib format, but must be available in dylib format
+
+metadata_target_not_installed =
+    the `{$locator_triple}` target may not be installed
+
+metadata_target_no_std_support =
+    the `{$locator_triple}` target may not support the standard library
+
+metadata_consider_downloading_target =
+    consider downloading the target with `rustup target add {$locator_triple}`
+
+metadata_std_required =
+    `std` is required by `{$current_crate}` because it does not declare `#![no_std]`
+
+metadata_consider_building_std =
+    consider building the standard library from source with `cargo build -Zbuild-std`
+
+metadata_compiler_missing_profiler =
+    the compiler may have been built without the profiler runtime
+
+metadata_install_missing_components =
+    maybe you need to install the missing components with: `rustup component add rust-src rustc-dev llvm-tools-preview`
+
+metadata_cant_find_crate =
+    can't find crate
+
+metadata_crate_location_unknown_type =
+    extern location for {$crate_name} is of an unknown type: {$path}
+
+metadata_lib_filename_form =
+    file name should be lib*.rlib or {dll_prefix}*.{dll_suffix}

compiler/rustc_errors/Cargo.toml

@@ -15,13 +15,14 @@ rustc_macros = { path = "../rustc_macros" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_lint_defs = { path = "../rustc_lint_defs" }
+rustc_target = { path = "../rustc_target" }
 unicode-width = "0.1.4"
 atty = "0.2"
 termcolor = "1.0"
 annotate-snippets = "0.9"
 termize = "0.1.1"
-serde = { version = "1.0.125", features = ["derive"] }
+serde = { version = "1.0.125", features = [ "derive" ] }
 serde_json = "1.0.59"
 
 [target.'cfg(windows)'.dependencies]
-winapi = { version = "0.3", features = ["handleapi", "synchapi", "winbase"] }
+winapi = { version = "0.3", features = [ "handleapi", "synchapi", "winbase" ] }

compiler/rustc_errors/src/diagnostic.rs

@@ -10,6 +10,7 @@ use rustc_lint_defs::{Applicability, LintExpectationId};
 use rustc_span::edition::LATEST_STABLE_EDITION;
 use rustc_span::symbol::{Ident, MacroRulesNormalizedIdent, Symbol};
 use rustc_span::{edition::Edition, Span, DUMMY_SP};
+use rustc_target::spec::PanicStrategy;
 use std::borrow::Cow;
 use std::fmt;
 use std::hash::{Hash, Hasher};
@@ -144,6 +145,12 @@ impl IntoDiagnosticArg for usize {
     }
 }
 
+impl IntoDiagnosticArg for PanicStrategy {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.desc().to_string()))
+    }
+}
+
 impl<'source> Into<FluentValue<'source>> for DiagnosticArgValue<'source> {
     fn into(self) -> FluentValue<'source> {
         match self {

compiler/rustc_metadata/src/creader.rs

@@ -750,13 +750,10 @@ impl<'a> CrateLoader<'a> {
         // Sanity check the loaded crate to ensure it is indeed a panic runtime
         // and the panic strategy is indeed what we thought it was.
         if !data.is_panic_runtime() {
-            self.sess.emit_err(CrateNotPanicRuntime { crate_name: name.to_string() });
+            self.sess.emit_err(CrateNotPanicRuntime { crate_name: name });
         }
         if data.required_panic_strategy() != Some(desired_strategy) {
-            self.sess.emit_err(NoPanicStrategy {
-                crate_name: name.to_string(),
-                strategy: desired_strategy.desc().to_string(),
-            });
+            self.sess.emit_err(NoPanicStrategy { crate_name: name, strategy: desired_strategy });
         }
 
         self.cstore.injected_panic_runtime = Some(cnum);
@@ -784,7 +781,7 @@ impl<'a> CrateLoader<'a> {
 
         // Sanity check the loaded crate to ensure it is indeed a profiler runtime
         if !data.is_profiler_runtime() {
-            self.sess.emit_err(NotProfilerRuntime { crate_name: name.to_string() });
+            self.sess.emit_err(NotProfilerRuntime { crate_name: name });
         }
     }
 
@@ -828,8 +825,8 @@ impl<'a> CrateLoader<'a> {
                 match global_allocator {
                     Some(other_crate) => {
                         self.sess.emit_err(ConflictingGlobalAlloc {
-                            crate_name: data.name().to_string(),
-                            other_crate_name: other_crate.to_string(),
+                            crate_name: data.name(),
+                            other_crate_name: other_crate,
                         });
                     }
                     None => global_allocator = Some(data.name()),
@@ -874,9 +871,9 @@ impl<'a> CrateLoader<'a> {
             let data = self.cstore.get_crate_data(dep);
             if needs_dep(&data) {
                 self.sess.emit_err(NoTransitiveNeedsDep {
-                    crate_name: self.cstore.get_crate_data(krate).name().to_string(),
-                    needs_crate_name: what.to_string(),
-                    deps_crate_name: data.name().to_string(),
+                    crate_name: self.cstore.get_crate_data(krate).name(),
+                    needs_crate_name: what,
+                    deps_crate_name: data.name(),
                 });
             }
         }

compiler/rustc_metadata/src/dependency_format.rs

@@ -140,7 +140,7 @@ fn calculate_type(tcx: TyCtxt<'_>, ty: CrateType) -> DependencyList {
                 if src.rlib.is_some() {
                     continue;
                 }
-                sess.emit_err(RlibRequired { crate_name: tcx.crate_name(cnum).to_string() });
+                sess.emit_err(RlibRequired { crate_name: tcx.crate_name(cnum) });
             }
             return Vec::new();
         }
@@ -224,10 +224,7 @@ fn calculate_type(tcx: TyCtxt<'_>, ty: CrateType) -> DependencyList {
                     Linkage::Static => "rlib",
                     _ => "dylib",
                 };
-                sess.emit_err(LibRequired {
-                    crate_name: tcx.crate_name(cnum).to_string(),
-                    kind: kind.to_string(),
-                });
+                sess.emit_err(LibRequired { crate_name: tcx.crate_name(cnum), kind: kind });
             }
         }
     }
@@ -251,8 +248,7 @@ fn add_library(
             // This error is probably a little obscure, but I imagine that it
             // can be refined over time.
             if link2 != link || link == RequireStatic {
-                tcx.sess
-                    .emit_err(CrateDepMultiple { crate_name: tcx.crate_name(cnum).to_string() });
+                tcx.sess.emit_err(CrateDepMultiple { crate_name: tcx.crate_name(cnum) });
             }
         }
         None => {
@@ -347,8 +343,8 @@ fn verify_ok(tcx: TyCtxt<'_>, list: &[Linkage]) {
 
         if tcx.is_panic_runtime(cnum) {
             if let Some((prev, _)) = panic_runtime {
-                let prev_name = tcx.crate_name(prev).to_string();
-                let cur_name = tcx.crate_name(cnum).to_string();
+                let prev_name = tcx.crate_name(prev);
+                let cur_name = tcx.crate_name(cnum);
                 sess.emit_err(TwoPanicRuntimes { prev_name, cur_name });
             }
             panic_runtime = Some((
@@ -370,8 +366,8 @@ fn verify_ok(tcx: TyCtxt<'_>, list: &[Linkage]) {
         // our same strategy.
         if found_strategy != desired_strategy {
             sess.emit_err(BadPanicStrategy {
-                runtime: tcx.crate_name(runtime_cnum).to_string(),
-                strategy: desired_strategy.desc().to_string(),
+                runtime: tcx.crate_name(runtime_cnum),
+                strategy: desired_strategy,
             });
         }
 
@@ -390,17 +386,17 @@ fn verify_ok(tcx: TyCtxt<'_>, list: &[Linkage]) {
 
             if let Some(found_strategy) = tcx.required_panic_strategy(cnum) && desired_strategy != found_strategy {
                 sess.emit_err(RequiredPanicStrategy {
-                    crate_name: tcx.crate_name(cnum).to_string(),
-                    found_strategy: found_strategy.desc().to_string(),
-                    desired_strategy: desired_strategy.desc().to_string() });
+                    crate_name: tcx.crate_name(cnum),
+                    found_strategy,
+                    desired_strategy});
             }
 
             let found_drop_strategy = tcx.panic_in_drop_strategy(cnum);
             if tcx.sess.opts.unstable_opts.panic_in_drop != found_drop_strategy {
                 sess.emit_err(IncompatiblePanicInDropStrategy {
-                    crate_name: tcx.crate_name(cnum).to_string(),
-                    found_strategy: found_drop_strategy.desc().to_string(),
-                    desired_strategy: tcx.sess.opts.unstable_opts.panic_in_drop.desc().to_string(),
+                    crate_name: tcx.crate_name(cnum),
+                    found_strategy: found_drop_strategy,
+                    desired_strategy: tcx.sess.opts.unstable_opts.panic_in_drop,
                 });
             }
         }